Huge gas pressure drop between meter and boiler. Help!

[DP]

Mainly because of the high boiler output, much higher than a typical house needs. But of course it might be a huge house.

Did you know there are appliances often fitted that have an input around 24kw and that is not taking into consideration any radiators.

 

[ScottishGasMan]

I just meant that if he was replacing like for like, he might argue that as the previous set-up was OK, and the gas flow hadn't changed, there was no need to check the gas pipe.

But its not an argument. Its his lawful duty to install the appliance safely and to spec. There's no guessing. You test it, it doesn't pass, then it can't be commissioned.

 

[DP]

….

 

[BlueLoo]

Mainly because of the high boiler output, much higher than a typical house needs. But of course it might be a huge house.

It would want to be huge (or uninsulated) for a 30kw boiler no?
Mine is ancient and 15kw is more than ample for this semi-d.

The gas bill must be quite something.

Edit: if spec'd properly. I read that installers have a habit of vastly over sizing boilers.

 

[fixitflav]

But its not an argument. Its his lawful duty to install the appliance safely and to spec. There's no guessing. You test it, it doesn't pass, then it can't be commissioned.

I didn't say it was much of a case, just something that the installer might try to argue.

 

[fixitflav]

Did you know there are appliances often fitted that have an input around 24kw and that is not taking into consideration any radiators.

I don't follow. If not taking into consideration any radiators, where is the heat going?
I'm sure there's a whole range of boiler inputs (and outputs) out there.

 

[fixitflav]

Nevertheless, it changes nothing. the boilers running safe. so I'd not loose any sleep over it. If working pressure is lower than 13mbar next service with meter pressure still the same then you can assume there is a restriction building in the gas line.

Yeah, that would be my option a).

 

[fixitflav]

Although you do lose the ability to simultaineously heat water and the radiators. It will only do one or the other at any point in time, prioritising heating the water until demand is satisfied.

I seem to remember we discussed this at some length in a thread a few weeks ago Harry

 

[Madrab]

Deary me .... are we seriously up to 11 pages with this FFS

Is there really any need for it? I'm sure the OP is seriously lost now ... or maybe not

 

[fixitflav]

I’m confused. It’s not blank- there are some figures on it but to be fair I have no idea what they relate to and or if they’re correct.

he’s coming tomorrow- any advice on what to ask him or tell him to do?

You could explain the benchmark form wasn't completed properly, and there appears to be excessive pressure drop.
I think he should install a pressure tapping point on the gas pipe just before the boiler, and then do a thorough pressure drop test.
Depending on the results, you could look at the options in #115 (there have been a couple of comments).

For background, do you know the output of the previous boiler?

 

[FiremanT]

Deary me .... are we seriously up to 11 pages with this FFS

Is there really any need for it? I'm sure the OP is seriously lost now ... or maybe not

You are correct. 11 pages of mainly guesswork and verbal diarrhoea.
It is impossible for anyone to read through this and make sense of it.

 

[fixitflav]

Safe but not correct surely?

You won't be condensing at 65c return will you, nor will you have a working bypass?
(Unless it's not needed and has been locked down)?

Whether or not it condenses also depends on the rad area. If the rads are too small, in cold weather the water temperature to give adequate heating will be too high for condensation.
I don't think the control-stat setting is that critical, as when the weather is moderately cold the roomstat is satisfied and switches off the boiler before control-stat temperature is reached. Up to that point, flow and return temperatures settle at what is needed to dissipate the boiler output, which could allow condensation. Maybe a bit different with a modulating boiler, but that's how I see it. I have W-plan and the control-stat setting is never reached on CH, only on HW.

 

[fixitflav]

You are correct. 11 pages of mainly guesswork and verbal diarrhoea.
It is impossible for anyone to read through this and make sense of it.

Yes, but any more suggestions in response to the OP's #134? That might help him when the guy comes tomorrow.

 

[FiremanT]

Yes, but any more suggestions in response to the OP's #134? That might help him when the guy comes tomorrow.

How many times do you want it repeating.?
The pipework is either seriously restricted or, more likely, is undersized.
The false figures imply that he either knew it was wrong or did not bother to consider it.
I cannot see post numbers but on page 2 the OP describes the pipe run. Most of it is concealed. It seems likely that the first part is iron . If it is most of the rest will be, at least until it leaves the floor and enters the concealed wall. It exits the wall in 15mm, so it may well be the snr all the way down - the previous demand was about 50% of the current and was probably okay.

Any decent installer would know visually that there is an issue.

The OP needs to decide what he wants out of this and demand accordingly.

is the house pre 1970?
Can the Op Accurately measure the diameter of the iron, and maybe post a photo?

 

[DP]

I don't follow. If not taking into consideration any radiators, where is the heat going?

That is the point. I as a heating engineer will take into consideration system configuration whereas a lay person may not.
Another hint- it is a system boiler perhaps?